After I've been logged in for a few weeks, this python process (same as in the bug description) gets to using half a gig or more of ram on my laptop; killing the process noticeably improves system responsiveness. It seems like the fix ought to be part of an update for Lucid.

Li Daobing's suggestion (#8) to update from Shawn P Huang's PPA does seem to help the problem quite a bit. There is a much much smaller leak of about 2 bytes per input method switch, but that is much better than the version in 10.4

Confirmed:
Uptime of my notebook is 19 days now, and this little plugin has already climbed up to 520MB. Clicking to restart removes the process, eventhough I have 4GB of memory, spending one eight of it for an IME tool seems a bit much ^^

Installing newest iBus from Shawn P. Huang's PPA made my input method (ibus-unikey) unusable. I have asked him on the iBus user mailing list several times but somehow my post were never moderated. Disappointed...

Hi. Mine does not get to aforementioned extremes, but it might if my uptimes get longer (which is inhibited by another issue) Well using "ibus-daemon --replace" is nice, although it leaves a zombie behind.
One could actually start or reissue "ibus-daemon --replace" in the limited shell. I use it for similar memory loving apps, like gnome-stardict
Say, start a terminal and execute

In my case Shawn Huang's ppa shawn-p-huang/ppa/ubuntu seems to fix it. The associated python process does not exceed 20MB. Although, the language window does not pop-up anymore, the ibus applet only shows the switch (maybe I have to logout-login). I am 100% satisfied with this.
Actually, apt-get could not handle the upgrade, aptitude could.